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Journal of Clinical Microbiology, October 2008, p. 3346-3354, Vol. 46, No. 10
0095-1137/08/$08.00+0     doi:10.1128/JCM.00995-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Molecular Characterization of Equine Rotavirus in Ireland

P. J. Collins,¹ A. Cullinane,² V. Martella,³ and H. O'Shea^1*

Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland,¹ Irish Equine Centre, Johnstown, Naas, County Kildare, Ireland,² Department of Animal Health and Wellbeing, Faculty of Veterinary Medicine of Bari, S.p. per Casamassima Km 3, 70010 Valenzano, Bari, Italy³

Received 23 May 2008/ Returned for modification 6 July 2008/ Accepted 7 August 2008

Top ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Group A rotaviruses are important causative agents of severe, acute dehydrating diarrhea in foals. A total of 86 rotavirus-positive fecal samples, collected from diarrheic foals from 11 counties in three of the four provinces of Ireland, were obtained from the Irish Equine Centre in Kildare during a 7-year (1999 to 2005) passive surveillance study and were characterized molecularly to establish the VP7 (G type) and VP4 (P type) antigenic specificities. Fifty-eight samples (67.5%) were found to contain G3 viruses, while in 26 samples (30.2%) the rotaviruses were typed as G14 and in 2 samples (2.3%) there was a mixed infection, G3 plus G14. All samples except for two, which were untypeable, were characterized as P[12]. Fifty-eight percent of the samples were obtained from County Kildare, the center of the Irish horse industry, where an apparent shift from G3P[12] to G14P[12] was observed in 2003. By sequence analysis of the VP7 protein, the G3 Irish strains were shown to resemble viruses of the G3A subtype (H2-like) (97.1 to 100% amino acid [aa] identity), while the G14 Irish strains displayed 93.9 to 97.1% aa identity to other G14 viruses. In the VP8* fragment of the VP4 protein, the P[12] Irish viruses displayed high conservation (92.3 to 100% aa) with other equine P[12] viruses. Worldwide, G3P[12] and G14P[12] are the most prevalent equine rotavirus strains, and G3P[12] vaccines have been developed for prevention of rotavirus-associated diarrhea in foals. Investigations of the VP7/VP4 diversity of the circulating equine viruses and the dynamics of strain replacement are important for better assessing the efficacies of the vaccines.

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Rotaviruses are classified into seven antigenically distinct groups (A to G) on the basis of a common group antigen, the inner capsid protein (VP6). Groups A, B, and C are associated with acute gastroenteritis in humans and animals, while groups D, E, F, and G have been detected only in animals (6, 35).

Group A rotaviruses (GARVs) are the main cause of acute dehydrating diarrhea in children and are associated with 400,000 to 500,000 deaths annually, mainly in developing countries (44). GARVs are nonenveloped icosahedral particles composed of 11 segments of double-stranded RNA (dsRNA) enclosed in a triple-layered protein capsid (6).

The two outer capsid proteins, VP7 and VP4, independently elicit neutralizing antibodies, induce protective immunity, and are used to classify rotaviruses into G (for glycoprotein) and P (for protease-sensitive) types, respectively (6). To date, 19 G types and 27 P types have been identified in humans and animals (36, 40, 41, 50).

Equine GARV is the main cause of diarrhea in foals up to 3 months of age, causing severe economic loss due to morbidity and mortality in studs (5, 26, 29). Typically, the disease induced by equine GARV is manifested by profuse watery diarrhea, dehydration, anorexia, abdominal pain, and depression (25, 49). Although the disease is self-limiting, the dehydration may be fatal, especially in young foals (10, 14, 51, 52).

Serological surveys have detected antibody in most adult horses, suggesting that equine rotaviruses are ubiquitous (10, 15, 21, 46). Equine GARVs have been identified in the feces of diarrheic foals in Britain (17), the United States (10, 34), Australia (52, 55), New Zealand (11), Ireland (51), and Japan (24). It has been shown that 15 to 50% of diarrheal foals shed rotaviruses (12, 26).

Antigenic/genetic characterization of equine GARVs identified in Japan, Australia, the United Kingdom, and Germany has revealed that most strains are either G3P[12] or G14P[12] (5, 16, 33, 54). Inactivated vaccines based on strains H2 and HO-5, G3P[12], have been developed for the prevention of rotavirus-associated diarrhea in foals. However, due to the limited number of studies, information on the diversity of equine GARVs is incomplete. There is evidence that horses can also be infected by strains displaying unique antigenic/genetic features, such as strain L338, G13P[18] (32), and the porcine-like virus H-1, G5P[7] (9), or by bovine-like GARVs G10P[1] and G8P[1] (28, 29, 33). Accordingly, gathering information on the antigenic diversity of equine GARVs is pivotal for evaluation of vaccine efficacy (2, 47), for understanding the reasons behind vaccine breakthroughs, and for implementing prophylactic measures.

Ireland is the third largest producer of thoroughbred foals in the world. Approximately 10,000 thoroughbred foals are born in Ireland every year, and they account for over 42% of the thoroughbred foals produced in Europe (31). Passive surveillance for GARVs in horses is being conducted at the Irish Equine Centre (Republic of Ireland). In this study, a collection of equine GARVs, detected between 1999 and 2005, was analyzed by PCR genotyping and sequence analysis of the main antigenic determinants VP7 and VP4, in order to collate information on the genetic/antigenic diversity of the circulating viruses.

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Sample collection and preparation. A total of 86 fecal samples (collected from 1999 to 2005) were obtained from the Irish Equine Centre in Johnstown, County Kildare. The samples were submitted to the Centre by veterinary practices located in 11 counties in three of the four provinces of Ireland. The samples were submitted to the Irish Equine Centre specifically for rotavirus testing from referring veterinary practices in Ireland. The samples had tested positive to rotavirus by latex agglutination and were stored at –80°C.

dsRNA preparation. Total nucleic acids were extracted from the samples by a standard phenol-chloroform method with ethanol precipitation. The extracted nucleic acids were resuspended in 100 µl of sterile diethyl pyrocarbonate-H₂O and stored at –80°C prior to use.

RT-PCR amplification of VP7 (G) typing. The dsRNA extracted from the fecal samples was denatured in 50% dimethyl sulfoxide at 97°C for 5 min and immediately cooled on ice. For amplification of VP7, the primer pair Beg9/End 9 was used (22) (Table 1), in a one-step reverse transcription-PCR (RT-PCR) protocol using an enhanced avian reverse transcriptase kit (Sigma-Aldrich). The reaction was carried out on an MJ Research PTC-200 thermocycler (GMI Inc., MN). For RT-PCR the following conditions were applied: 45°C for 30 min and 70°C for 4 min, followed by 35 cycles of 94°C for 1 min, 55°C for 30 s, and 68°C for 2 min, plus a final extension of 68°C for 5 min. The amplicons were analyzed in 1.5% agarose gels following ethidium-bromide staining and UV light transillumination.

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TABLE 1. Nucleotide sequences and positions of the primers used for detection and characterization of GARVs

Prediction of the VP7 (G) type was carried out using a pool of primers, including the G3- and G14-specific oligonucleotides described by Tsunemitsu et al. (54) and primer End9 (22). The amplicons obtained in the first-round amplification were diluted 1:400 and used as templates for the second-round PCR, as described by Elschner et al. (16) with minor modifications. The thermal program was as follows: 94°C for 5 min followed by 35 cycles of 94°C for 30 s, 54°C for 1 min, and 72°C for 1 min, and a final extension at 72°C for 10 min.

RT-PCR amplification of the VP8* subunit and VP4 (P) typing. For amplification of the VP8* subunit of the VP4 gene, the primers Con2 and Con3 were used (20) (Table 1), applying the same thermal conditions as those used for amplification of the VP7 gene. Prediction of the VP4 (P) type was accomplished using a pool of primers, including the P[12]- and P[18]-specific oligonucleotides described by Fukai et al. (19) and primer Con3 (20). Identical reaction and thermal conditions were used as those described for the G typing PCR.

Sequence analysis of VP7 and VP4 and genes of equine group A rotavirus. Based on the genotyping results, four G3 and two G14 strains were selected for sequence analysis of the VP7 gene. Also, the VP8* amplicons of six P[12] strains were selected for sequencing. The first-round PCR products obtained with primers Beg9/End9 and Con2/Con3 were purified using a QIAquick PCR purification kit (Qiagen Ltd., West Sussex, England) and sequenced by MWG Biotech (Ebersberg, Germany).

The sequences were assembled, edited, and analyzed using the Bioedit software package version 2.1 (23). Preliminary analysis was accomplished by comparison with the sequences available in the database using the web-based programs BLAST (http://www.ncbi.nlm.nih.gov/BLAST) and FASTA (http://www.ebi.ac.uk/fasta33).

Phylogenetic and molecular evolutionary analyses were conducted using MEGA version 2.1 (Arizona State University) (38). Phylogenetic trees, based on VP4 and VP7 (Fig. 1 and 2, respectively) were constructed using reference strains obtained from the GenBank database (listed in Tables 2 and 3) and were elaborated with both parsimony and distance methods, supplying a statistical support with bootstrapping over 100 replicates.

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FIG. 1. Neighbor-joining tree based on the VP4 amino acid sequence of equine GARVs described in this study and reference strains (Table 3). The tree was rooted using human strain 69 M, P[10].

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FIG. 2. Neighbor-joining tree based on the VP7 amino acid sequence of equine GARVs described in this study and reference strains (Table 2). The tree was rooted using bovine strain 61A, G10.

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TABLE 2. VP7 reference strains, with genotype designations and accession numbers

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TABLE 3. VP4 reference strains, with genotype designations and accession numbers

Nucleotide sequence accession numbers. The partial sequences of the VP7 strains 36363/99/Ire, 41276/00/Ire, 4539/02/Ire, 52634/01/Ire, 41568/00/Ire, and 54690/01/Ire have been registered in GenBank under the accession numbers EU717533, EU717534, EU717535, EU717536, EU717537, and EU717538, respectively. The partial sequences of the VP8* subunit of the VP4 of strains 12619/05/Ire, 17132/04/Ire, 41568/00/Ire, 6214/02/Ire, 36366/99/Ire, and 4954/03/Ire have been registered in GenBank under the accession numbers EU717539, EU717540, EU717541, EU717542, EU717543, and EU717544.

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Establishment of VP7 and VP4 genotypes by PCR genotyping. Eighty-six rotavirus-positive fecal samples from diarrheic foals submitted to the Irish Equine Centre in Kildare between 1999 and 2005 were included in this study. The majority (74/86; 86%) of the GARV strains were detected between February and May (Fig. 3). The observed seasonality of rotavirus-associated disease in foals is due to the management of horse reproduction, with foaling being concentrated in late winter and spring. Twelve samples were submitted between June and August.

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FIG. 3. Seasonality of equine GARV strains between February and August (1999 to 2005) and the distribution of the G types.

By PCR genotyping, a total of 58 samples (67.5%) were characterized as G3, 26 samples (30.2%) were typed as G14, and 2 samples (2.3%) were found to be mixed infections, G3 plus G14. Almost all the samples (84/86; 98%) were characterized as P[12] by PCR, while for two samples no amplicon was obtained in either the first- or second-round amplification.

Sequence analysis of VP7 of G3 equine rotaviruses. In order to confirm the results of the PCR genotyping and to collect molecular epidemiological information, the VP7 sequences of six equine GARVs, four G3P[12] and two G14P[12], were determined. In VP7, the sequence of the Irish G3 strains displayed 97.8% to 99.2% amino acid (aa) identity to each other and the highest identity (97.8 to 100%) to the G3A German strain 4616G11. Identity to the reference strain H2 ranged from 97.1 to 99.2% (Table 4). In the phylogenetic tree (Fig. 2), the G3 Irish strains were clustered with G3A equine rotavirus (H2-like). An alignment of the VP7 antigenic regions A (aa 87 to 101), B (aa 141 to 152), C (aa 208 to 224), and F (235 to 242) was made (Fig. 4) (7, 13, 37, 43). The Irish strains were highly conserved with respect to the G3A German strain 4616G11 and differed only in one residue, 216-TE (region C) from the G3A strain H2, and in two amino acids, 215-FI (region C) and 242-AT (region F), from the G3A strain ERV316. Conversely, the Irish G3 strains differed in at least six residues, 90-AV, 91-TA (region A), 212-VT, 213-AT, 217-IV (region C), and 242-AS (region F), from the Japanese G3B equine strains (HO-5) and from the American G3B strain FI-14.

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TABLE 4. VP7 comparisons (amino acid identity) between the Irish equine GARVs detected in this study and other equine GARVs

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FIG. 4. Comparison of the deduced equine VP7 amino acid sequence in the VP7 antigenic regions A (aa 87 to 101), B (aa 141 to 152), C (aa 208 to 224), and F (aa 235 to 242) from animal GARVs. The genotypes of GARVs are also given. Identical amino acids are indicated by a dot.

Sequence analysis of the VP7 of G14 equine rotaviruses. In VP7, the Irish G14 strains 41568/00/Ire and 54690/01/Ire displayed 97.8% aa identity to each other. The highest identity (95.0% to 97.1%) was to the Japanese strains JE77 and JE91 (Table 4). Strain 54690/01/Ire differed only in one residue (151-MI, region B) from the Venezuelan strain FR8, in four residues (213EA, region C, 238-240-INVVEC, region F) from the American strain FI23, and in one change, 238-ND (region F), from the Japanese strains. In addition, strain 41568/00/Ire displayed two unique changes, 93-IV (region A) and 222-EQ (region C) (Fig. 4).

Sequence analysis of the VP8* subunit of VP4. In order to confirm the results of the PCR genotyping, the VP8* sequences of six equine GARVs, four G3P[12] and two G14P[12] sequences, were determined. The strains were confirmed to be P[12], since they displayed 99.6 to 100% aa identity to P[12] viruses H-O5 and ERV59. A phylogenetic tree was elaborated (Fig. 1), based on the VP8* fragment of the VP4 gene. From the phylogenetic tree, four lineages were observed. Four Irish strains, 12619/05/Ire, 6214/02/Ire 36366/99/Ire, and 4954/03/Ire, clustered with Japanese, German, and American strains JE-75, JE-77, 4698G5, 4775G7, FI-23, and FI-14. The Irish strain 41568/00/Ire clustered with French and German strains N1A00, 4702G1, and N1D00. The Irish strain 17132/04/Ire clustered with the French and German strains N1C00, N5A01, and 4766G3.

Top ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
GARVs are an important cause of acute gastroenteritis in foals (5, 26, 29). Surveillance for GARV infection in thoroughbred foals with enteritis in Ireland during 1999 to 2005 revealed a marked seasonal pattern of GARV-associated disease. The vast majority of the GARV strains (74/86; 86%) were detected between February and May (Fig. 3), when the majority of foaling is concentrated and susceptible hosts (foals less than 3 months of age) are more available. Such seasonality raises the question of whether infectivity of equine GARVs can be maintained for a long period of time on stud farms or whether there are unknown mechanisms of persistence of rotaviruses. The stability and infectivity of rotaviruses can be maintained for up to 32 months in fecal samples of piglets (48). Also, it can be speculated that GARVs may circulate in an asymptomatic fashion in nonsusceptible animals (39, 43, 45), due to an age-related mechanism of disease restriction (8) or to active immunization after previous infection or vaccination (53). Accurate measures of cleaning and disinfection are required in equine facilities, although meticulous environmental disinfection procedures do not appear to remove completely rotavirus environmental contamination (56).

During a 7-year time span (1999 to 2005), 86 cases of enteritis in foals were found to be associated with GARV infection. By PCR genotyping with specific primers, 58 samples (67.5%) were found to contain G3P[12] GARVs, while 26 samples (30.2%) contained G14P[12] viruses and 2 samples (2.3%) were mixed infections, G3 plus G14P[12]. GARVs with G3P[12] specificity appear to be widespread in horses, since they account for about 86%, 87%, 86%, and 84.6% of the infections detected in horses in Japan, Australia, the United Kingdom, and Germany, respectively (5, 16, 33, 54). Almost all of the Irish strains (98%) possessed a P[12] VP4 genotype. This P type appears to be predominant in equine GARVs (5, 16, 32), although other P types have also been identified sporadically, such as P[1], P[7], and P[18] (9, 27, 28, 32, 33).

By temporal and geographical dissection of the obtained data (Fig. 5), we observed that in the study period the majority of the rotavirus-positive samples (58%) were submitted from veterinary practices in County Kildare. Kildare is the center of the Irish horse industry and has more stud farms than any other county in Ireland. Rotavirus-associated cases of enteritis occurred in a scattered fashion in several Irish counties apart from Kildare. Indeed, in County Kildare, rotavirus enteritis cases were described yearly and it was possible to observe an apparent temporal shift from G3 to G14 viruses. G14 viruses appeared in 2001 and tended to replace G3 GARVs starting in 2003. We also observed that years with low rotavirus activity were intermingled with years of intense rotavirus activity. Interestingly, a temporal shift from G3 to G14 viruses has been also documented in horse farms in Hokkaido Prefecture, Japan (54). Longitudinal studies in settled human and animal populations have revealed similar temporal fluctuations in the circulating G/P rotavirus types (1, 18). These changes are likely driven by mechanisms of immune escape that decrease the population immune pressure against the virus.

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FIG. 5. Distribution of the G types in Ireland from 1999 to 2005. The G3 strains are designated by a star. The G14 strains are designated by an unfilled circle. The equine GARV samples were submitted from veterinary practices in 11 counties in three provinces. The samples from County Kildare are enclosed within a square.

In order to investigate the genetic relationships between the Irish equine GARVs and the previously characterized equine GARV strains identified in other geographical settings, including the vaccine strains H-2 and HO-5, we determined the sequence of the VP7 and VP4 genes of G3P[12] and G3P[14] viruses identified in this study. In VP7, the G3 Irish GARV strains displayed 97.8 to 99.2% aa identity to each other, 97.1 to 99.2% aa identity to the vaccine strain H-2 (G3AP[12]), and 92.9 to 94.3% aa identity to the candidate vaccine strain HO-5 (G3BP[12]) (Table 4). In the phylogenetic tree (Fig. 2), the G3 Irish strains were clustered with the German G3A equine strain 4766G3. In the VP7 antigenic regions A, B, C, and F (Fig. 4), the Irish strains were highly conserved with respect to the G3A German strain 4616G11. The Irish G3 strains differed in only one residue from the G3A strain H-2 and in two residues from the G3A strain ERV316. Conversely, the Irish G3 strains differed in at least six residues from the Japanese G3B equine strains and from the American G3B strain FI-14. The distinction of G3 equine viruses into two antigenic subtypes, G3A and G3B, was based on cross-neutralization assays and on different reactivities with panels of monoclonal antibodies (4). Such antigenic differences rely on at least 6 aa residues in regions A to F. The American strain H2 and the Japanese strain HO-5, both used for vaccination purposes, belong to different G3 subtypes, G3A and G3B, respectively, and differ in six residues (90 AV, 91 TA, 212 VT, 213 AT, 218 IV, and 242 AS). Interestingly, there is also evidence for the existence of G3 equine GARVs that markedly differ from both G3A and G3B equine GARVs (Fig. 2 and 4), thus suggesting a broader genetic/antigenic heterogeneity. Intraserotypic variation (antigenic drift) has been observed in G1 human GARVs circulating in a settled population with repeated introduction and/or reintroduction of G1 variants, a pattern that is consistent with mechanisms of antigenic escape (1).

The sequences of the VP7 genes of two G14 strains, 41568/00/Ire and 54690/01/Ire, were also determined. The two Irish G14 strains displayed 97.8% aa identity to each other. The highest amino acid identity (95.0 to 97.1%) was to the Japanese strains JE77 and JE91 (Table 4). In the VP7 antigenic regions A to F, strain 54690/01/Ire differed in only one residue from the Venezuelan strain FR8 and from the Japanese strains and in four residues from the American strain FI23. Strain 41568/00/Ire appeared more diverse, since it displayed two unique changes, 93-IV (region A) and 222-EQ (region C) (Fig. 4).

In order to confirm the results of the PCR genotyping, the VP8* sequences of six equine strains were determined and analyzed. In VP8*, the Irish strains displayed low variation. However, phylogenetic analysis (Fig. 1) revealed at least four lineages, among which the equine strains clustered regardless of their G type and geographical origin, a finding that is consistent with repeated exchange of virus strains by animal trading or the movement of animals for competitions and with reassortment (42), which may occur frequently in the field during mixed infections.

Epidemiological investigations to assess the genetic/antigenic diversity of equine GARVs are regarded as fundamental for evaluating the dynamics of replacement of the various GARV strains. In addition, since protective immunity appears to be primarily serotype specific (6) and there is concern that antigenic/genetic diversity might affect the efficacy of the vaccines to some extent, surveillance studies for GARVs are pivotal for better assessing the efficacies of the vaccines. Rotaviral diarrhea of foals heavily impacts horse breeding farms worldwide, and it is of particular relevance for Irish stud farms, as Ireland is a leading worldwide producer of thoroughbred foals. Several studies aimed at the development of effective and reliable vaccines for rotavirus-associated disease in foals have been conducted, and a vaccine based on the American strain H2, G3AP[12], has been available since the mid 1990s in the European market, while the Japanese strain HO-5, G3BP[12], has been used to develop a candidate equine rotavirus vaccine in Japan (30).

Immunization of pregnant mares with inactivated vaccines based on homologous (equine) virus either alone or in conjunction with heterologous (simian or bovine) GARV strains reduced the incidence of rotaviral diarrhea in foals born to vaccinated mares, compared with foals born to unvaccinated mares (2, 47). It is unclear whether the antigenic/genetic diversity observed in equine GARVs may affect vaccine-induced protection against rotaviral diarrhea in foals. Vaccination of mares with a bovine rotavirus vaccine produced a heterotypic antibody response in the milk which persisted for at least 2 months (3). However, vaccine breakthroughs due to G14P[12] GARV strains have been observed in animals immunized with the inactivated strain HO-5, G3BP[12] (30).

A vaccine containing strain H-2, G3AP[12], is licensed for use in Ireland, and this vaccine could be adequate, since G3P[12] viruses were predominant in Ireland from 1999 to 2005. However, 30.2% of the equine GARV strains were characterized as G14, and G14P[12] viruses were frequently detected in County Kildare between 2003 and 2005. Continual surveillance will be needed to better evaluate vaccine efficacy, to understand the reasons for vaccine breakdown, and to implement prophylactic measures.

 
* Corresponding author. Mailing address: Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland. Phone: 00353-21-4326370. Fax: 00353-21-4326951. E-mail: helen.oshea{at}cit.ie

Published ahead of print on 20 August 2008.

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1
1. Arista, S., G. M. Giammanco, S. De Grazia, S. Ramirez, C. Lo Biundo, C. Colomba, A. Cascio, and V. Martella. 2006. Heterogeneity and temporal dynamics of evolution of G1 human rotaviruses in a settled population. J. Virol. 80:10724-10733.[Abstract/Free Full Text]
2
2. Barrandeguy, M., V. Parreno, M. Lagos Marmol, F. Pont Lezica, C. Rivas, C. Valle, and F. Fernandez. 1998. Prevention of rotavirus diarrhoea in foals by parenteral vaccination of the mares: field trial. Dev. Biol. Stand. 92:253-257.[Medline]
3
3. Browning, G. F., R. M. Chalmers, C. H. S. Sale, T. A. Fitzgerald, and D. R. Snodgrass. 1991. Homotypic and heterotypic serum and milk antibody to rotavirus in normal, infected and vaccinated horses. Vet. Microbiol. 27:231-244.[CrossRef][Medline]
4
4. Browning, G. F., R. M. Chalmers, T. A. Fitzgerald, and D. R. Snodgrass. 1992. Evidence for two serotype G3 subtypes among equine rotaviruses. J. Clin. Microbiol. 30:485-491.[Abstract/Free Full Text]
5
5. Browning, G. F., and A. P. Begg. 1996. Prevalence of G and P serotypes among equine rotaviruses in the faeces of diarrhoeic foals. Arch. Virol. 141:1077-1089.[CrossRef][Medline]
6
6. Ciarlet, M., and M. K. Estes. 2002. Rotaviruses: basic biology, epidemiology and methodologies, p. 2753-2773. In G. Bitton (ed.), Encyclopedia of environmental microbiology. John Wiley and Sons, New York, NY.
7
7. Ciarlet, M., Y. Hoshino, and F. Liprandi. 1997. Single point mutations may affect the serotype reactivity of serotype G11 porcine rotavirus strains: a widening spectrum? J. Virol. 71:8213-8220.[Abstract]
8
8. Ciarlet, M., M. A. Gilger, C. Barone, M. McArthur, M. K. Estes, and M. E. Conner. 1998. Rotavirus disease, but not infection and development of intestinal histopathological lesions, is age restricted in rabbits. Virology 251:343-360.[CrossRef][Medline]
9
9. Ciarlet, M., P. Isa, M. E. Conner, and F. Liprandi. 2001. Antigenic and molecular analyses reveal that the equine rotavirus strain H-1 is closely related to porcine, but not equine, rotaviruses: interspecies transmission from pigs to horses? Virus Genes 22:5-20.[CrossRef][Medline]
10
10. Conner, M. E., and R. W. Darligton. 1980. Rotavirus infection of foals. Am. J. Vet. Res. 41:1699-1703.[Medline]
11
11. Durham, P. J. K., B. J. U. Stevenson, and B. C. Farquharson. 1979. Rotavirus and coronavirus associated diarrhoea in domestic animals. N. Z. Vet. J. 27:30-32.[Medline]
12
12. Dwyer, R. M., D. G. Powell, W. Roberts, M. Donahue, E. T. Lyons, M. Osborne, and G. Woode. 1990. A study of the etiology and control of infectious diarrhoea among foals in central Kentucky, p. 337-355. Proc. 36th Annu. Meet. Am. Assoc. Equine Pract. AAEP, Lexington, KY.
13
13. Dyall-Smith, M. L., I. Lazdins, G. W. Tregear, and I. H. Holmes. 1986. Location of the major antigenic sites involved in rotavirus serotype-specific neutralization. Proc. Natl. Acad. Sci. USA 83:3465-3468.[Abstract/Free Full Text]
14
14. Eichorn, W., P. A. Bachamnn, H. Werhahn, and R. Jacobi. 1986. Occurrence and isolation in tissue culture of equine rotaviruses. J. Vet. Med. B 33:155-159.
15
15. Eichorn, W., and C. C. Huan. 1987. Serological investigations on the prevalence of rotavirus in horses. Tierarztl. Umsch. 42:22-23.
16
16. Elschner, M., C. Schrader, H. Hotzel, J. Prudlo, K. Sachse, W. Eichhorn, W. Herbst, and P. Otto. 2004. Isolation and molecular characterization of equine rotaviruses from Germany. Vet. Microbiol. 105:123-129.[CrossRef]
17
17. Flewett, T. H., A. S. Bryden, and H. Davis. 1975. Virus diarrhoea in foals and other animals. Vet. Rec. 96:477.[Medline]
18
18. Fukai, K., Y. Maeda, K. Fujimoto, T. Itou, and T. Sakai. 2002. Changes in the prevalence of rotavirus G and P types in diarrheic calves from the Kagoshima prefecture in Japan. Vet. Microbiol. 86:343-349.[CrossRef][Medline]
19
19. Fukai, K., T. Saito, O. Fukuda, A. Hagiwara, K. Inoue, and M. Sato. 2006. Molecular characterisation of equine group A rotavirus, Nasuno, isolated in Tochigi Prefecture, Japan. Vet. J. 172:369-373.[CrossRef][Medline]
20
20. Gentsch, J. R., R. I. Glass, P. Woods, V. Gouvea, M. Gorziglia, J. Flores, B. K. Das, and M. K. Bhan. 1992. Identification of group A rotavirus gene 4 types by polymerase chain reaction. J. Clin. Microbiol. 30:1365-1373.[Abstract/Free Full Text]
21
21. Goto, H., H. Tsunemitsu, M. Horimoto, K. Shimizu, T. Urasawa, S. Urasawa, H. Ohishi, and Y. Ikemoto. 1981. A sero-epidemiological study on rotavirus infection in horses. Bull. Equine Res. Inst. 18:129-135.
22
22. Gouvea, V., R. I. Glass, P. Woods, K. Taniguchi, H. F. Clark, B. Forrester, and Z. Y. Fang. 1990. Polymerase chain reaction amplification and typing of rotavirus nucleic acid from stool specimens. J. Clin. Microbiol. 28:276-282.[Abstract/Free Full Text]
23
23. Hall, T. A. 1999. BioEdit: a user friendly biological sequence alignment and analysis program for Windows 95/98/NT. Nucleic Acids Symp. 41:95-98.
24
24. Imagawa, H., Y. Ando, T. Sugiura, R. Wada, K. Hirasawa, and Y. Akiyama. 1981. Isolation of a foal rotavirus in MA-104 cells. Bull. Equine Res. Inst. 18:119-128.
25
25. Imagawa, H., R. Wada, M. Kamada, T. Kumanomido, Y. Fukunaga, and K. Hirasawa. 1984. Experimental infection of equine rotavirus in foals. Bull. Equine Res. Inst. 21:65-71.
26
26. Imagawa, H., K. Sekiguchi, T. Anzai, Y. Fukunaga, T. Kanemaru, H. Ohishi, T. Higuchi, and M. Kamada. 1991. Epidemiology of equine rotavirus infection among foals in the breeding region. J. Vet. Med. Sci. 53:1079-1080.[Medline]
27
27. Imagawa, H., T. Tanaka, K. Sekiguchi, Y. Fukunaga, T. Anzai, N. Minamoto, and M. Kamada. 1993. Electropherotypes, serotypes and subgroups of equine rotaviruses isolated in Japan. Arch. Virol. 131:169-176.[CrossRef][Medline]
28
28. Imagawa, H., S. Ishida, S. Uesugi, K. Masanobu, Y. Fukunaga, and O. Nakagomi. 1994. Genetic analysis of equine rotaviruses by RNA-RNA hybridisation. J. Clin. Microbiol. 32:2009-2012.[Abstract/Free Full Text]
29
29. Imagawa, H., R. Wada, S. Sugita, and Y. Fukunaga. 1998. Passive immunity in foals of mares immunized with inactivated equine rotavirus vaccine, p. 201-205. In U. Wernery, J. A. Mumfold, and O. R. Kaaden (ed.), Equine infectious disease, vol. VIII. Publications Ltd., Newmarket, United Kingdom.
30
30. Imagawa, H., T. Kato, H. Tsunemitsu, H. Tanaka, S. Sato, and T. Higuchi. 2005. Field study of inactivated equine rotavirus vaccine. J. Equine Sci. 16:35-44.[CrossRef]
31
31. Indecon International. 2004. An assessment of the economic contribution of the thoroughbred breeding and horse racing industry in Ireland. A final report for the Irish Thoroughred Breeders' Association, European Breeders' Fund and Horse Racing Ireland. Indecon, Dublin, Ireland. www.goracing.ie/AssetLibrary/Files/HRI/Info/indeconReportJULY2004.pdf.
32
32. Isa, P., and D. R. Snodgrass. 1994. Serologic and genomic characterization of equine rotavirus VP4 proteins identifies three different P serotypes. Virology 201:364-372.[CrossRef][Medline]
33
33. Isa, P., A. R. Wood, T. Netherwood, M. Ciarlet, H. Imagawa, and D. R. Snodgrass. 1996. Survey of equine rotaviruses shows conservation of one P genotype in background of two G genotypes. Arch. Virol. 141:1601-1612.[CrossRef][Medline]
34
34. Kanitz, C. L. 1976. Identification of an equine rotavirus as a cause of neonatal foal diarrhoea, p. 155-165. Proc. 22nd Annu. Meet. Am. Assoc. Equine Pract. AAEP, Lexington, KY.
35
35. Kapikian, A. Z., Y. Hoshino, and R. M. Chanock. 2001. Rotaviruses, p. 1787-1883. In D. M. Knipe and P. M. Howley (ed.), Fields virology, 4th ed. Lippincott Williams & Wilkins, Philadelphia, PA.
36
36. Khamrin, P., N. Maneekarn, S. Peerakome, W. Chan-it, F. Yagyu, S. Okitsu, and H. Ushijima. 2007. Novel porcine rotavirus of genotype P[27] shares new phylogenetic lineage with G2 porcine rotavirus strain. Virology 361:243-252.[CrossRef][Medline]
37
37. Kobayashi, N., K. Taniguchi, and S. Urasawa. 1991. Analysis of the newly identified neutralization epitopes on VP7 of human rotavirus serotype 1. J. Gen. Virol. 72:117-124.[Abstract/Free Full Text]
38
38. Kumar, S., K. Tamura, I. B. Jakobsen, and M. Nei. 2001. MEGA2: molecular evolutionary genetics analysis software. Bioinformatics 17:1244-1245.[Abstract/Free Full Text]
39
39. Lecce, J. G., and M. W. King. 1978. Role of rotavirus (reo-like) in weanling diarrhoea of pigs. J. Clin. Microbiol. 8:454-458.[Abstract/Free Full Text]
40
40. Martella, V., M. Ciarlet, K. Banyai, E. Lorusso, S. Arista, A. Lavazza, G. Pezzotti, N. Decaro, A. Cavalli, M. S. Lucente, M. Corrente, G. Elia, M. Camero, M. Tempesta, and C. Buonavoglia. 2007. Identification of group A porcine rotavirus strains bearing a novel VP4 (P) genotype in Italian swine herds. J. Clin. Microbiol. 45:577-580.[Abstract/Free Full Text]
41
41. Matthijnssens, J., M. Ciarlet, E. Heiman, I. Arijs, T. Delbeke, S. McDonald, E. Palombo, M. Iturriza-Gomara, P. Maes, J. T. Patton, M. Rahman, and M. Van Ranst. 2008. Full genome-based classification of rotaviruses reveals common origin between human Wa-like and porcine rotavirus strains and human DS-1-like and bovine rotavirus strains. J. Virol. 82:3204-3219.[Abstract/Free Full Text]
42
42. Nguyen, T. A., P. Khamrin, Q. D. Trinh, T. G. Phan, D. le Pham, P. le Hoang, K. T. Hoang, F. Yagyu, S. Okitsu, and H. Ushijima. 2007. Sequence analysis of Vietnamese P[6] rotavirus strains suggests evidence of interspecies transmission. J. Med. Virol. 79:1959-1965.[CrossRef][Medline]
43
43. Nishikawa, K., Y. Hoshino, K. Taniguchi, K. Y. Green, H. B. Greenberg, A. Z. Kapikian, R. M. Chanock, and M. Gorziglia. 1989. Rotavirus VP7 neutralization epitopes of serotype 3 strains. Virology 171:503-515.[CrossRef][Medline]
44
44. Parashar, U. D., E. G. Hummelman, J. S. Bresee, M. A. Miller, and R. I. Glass. 2003. Global illness and deaths caused by rotavirus disease in children. Emerg. Infect. Dis. 9:565-572.[Medline]
45
45. Parra, G. I., G. Vidales, J. A. Gomez, F. M. Fernandez, V. Parreño, and K. Bok. 2008. Phylogenetic analysis of porcine rotavirus in Argentina: increasing diversity of G4 strains and evidence of interspecies transmission. Vet. Microbiol. 126:243-250.[CrossRef][Medline]
46
46. Pearson, N. J., R. W. Fulton, C. J. Issel, and W. T. Springer. 1982. Prevalence of rotavirus antibody in chickens and horses in Louisiana, USA. Vet. Rec. 110:58-59.[Medline]
47
47. Powell, D. J., R. M. Dwyer, J. L. Traub-Dargatz, R. H. Fulker, J. W. Whalen, Jr., J. Srinivasppa, W. M. Acree, and H. J. Chu. 1997. Field study of the safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. J. Am. Vet. Med. Assoc. 211:193-198.[Medline]
48
48. Ramos, A. P., C. C. Stefanelli, R. E. Linhares, B. G. de Brito, N. Santos, V. Gouvea, R. de Cassia Lima, and C. Nozawa. 2000. The stability of porcine rotavirus in faeces. Vet. Microbiol. 71:1-8.[CrossRef][Medline]
49
49. Scrutchfield, W. L., A. K. Eugster, H. Abel, Jr., and J. E. Ward, Jr. 1979. Rotavirus infections in foals, p.217-233. Proc. 25th Annu. Meet. Am. Assoc. Equine Pract. AAEP, Lexington, KY.
50
50. Steyer, A., M. Poljsak-Prijatelj, D. Barlic-Maganja, U. Jamnikar, J. Z. Mijovski, and J. Marin. 2007. Molecular characterization of a new porcine rotavirus P genotype found in an asymptomatic pig in Slovenia. Virology 359:275-282.[CrossRef][Medline]
51
51. Strickland, K. L., P. Lenihan, M. G. O'Connor, and J. C. Condon. 1982. Diarrhoea in foals associated with rotavirus. Vet. Rec. 111:421.[Medline]
52
52. Studdert, M. J., R. W. Mason, and B. E. Patten. 1978. Rotavirus diarrhoea of foals. Aust. Vet. J. 54:363-364.[CrossRef][Medline]
53
53. To, T. L., L. A. Ward, L. Yuan, and L. J. Saif. 1998. Serum and intestinal isotype antibody responses and correlates of protective immunity to human rotavirus in a gnotobiotic pig model of disease. J. Gen. Virol. 79:2661-2672.[Abstract]
54
54. Tsunemitsu, H., H. Imagawa, M. Togo, T. Shouji, K. Kawashima, R. Horino, K. Imai, T. Nishimori, M. Tagaki, and T. Higuchi. 2001. Predominance of G3B and G14 equine group A rotavirus of a single VP4 serotype in Japan. Arch. Virol. 146:1949-1962.[CrossRef][Medline]
55
55. Tzipori, S., and M. Walker. 1978. Isolation of rotavirus from foals with diarrhoea. Aust. J. Exp. Biol. Med. Sci. 56:453-457.[CrossRef][Medline]
56
56. Widdowson, M. A., G. J. van Doornum, W. H. van der Poel, A. S. de Boer, R. van de Heide, U. Mahdi, P. Haanen, J. L. Kool, and M. Koopmans. 2002. An outbreak of diarrhea in a neonatal medium care unit caused by a novel strain of rotavirus: investigation using both epidemiologic and microbiological methods. Infect. Control Hosp. Epidemiol. 23:665-670.[CrossRef][Medline]

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Journal of Clinical Microbiology, October 2008, p. 3346-3354, Vol. 46, No. 10
0095-1137/08/$08.00+0     doi:10.1128/JCM.00995-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

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